It's too much of a shopping list, and especially to start off.
For kegging, you need:
- a keg ;)
- a way to introduce CO₂
- a way to dispense beer
From what you've listed, you will need either:
- the regulator, and also:
- a CO₂ tank to go along with it (not listed)
- gas-line tubing from the regulator to the gas quick disconnect (QD) you listed
- the gas QD you listed
- or, the hand-held "CO₂ Charger" thing
- note that this includes a gas QD
But you don't need both. And you really want the CO₂ tank; 5lb is a common size, and will last a handful of batches. Those handheld chargers are not anything but an emergency/party measure.
For dispensing beer, you need either:
- the "beer tap" you listed
- note that this includes a liquid QD, a bit of tubing, and a "picnic" faucet to control the pouring
- or, the combination of:
- a liquid QD, as listed
- beer-line tubing, as listed
- some sort of faucet (as listed, except not)
I would start off with the beer tap. It has an unfortunately-too-short beer-line length, but it's cheap and will work out of the box.
If you are interested in the beer faucet/tap, note that you would also need some way to mount that faucet such that you can actually pull the handle. Usually this is done by mounting the shank through some sort of wall or draft-line riser. The faucet connects to the shank on one end, the shank has an end-cap that the beer line connects to, and the beer line continues on to the liquid QD.
You do not want chrome-plated taps. Beer has a low pH, and will strip the chrome off the tap, over time. Stainless steel is the only way to go.
Note that I specify "gas QD" and "liquid QD" above. They are not interchangeable; gray=gas, black=beer.
Note that pin-lock and ball-lock kegs are two different things; their disconnects are not interchangeable.
I mentioned the "too-short" beer line length, above. The line length (and a couple of other properties) determines how much "resistence" the line provides. An ideally-balanced draft system is one where the CO₂ regulator is providing the appropriate amount of pressure to keep the beer at its style-dependent ideal carbonation, and then the dispensing side of the draft system is tuned such that by the time the beer reaches the glass, almost all the pressure is "consumed", leading to a pour that's of sufficient speed without over or under foaming.
So, the (apparently) very short beer-line length on the "beer tap" is going to lead to an out of balance system. But I over state this, it is not a big deal, especially getting started. I used a similar picnic tap for a couple of years before building a keezer with proper faucets.
You can probably get:
- 5ft of beer line
- a barbed liquid QD
- barbed picnic tap
for roughly the same price as the pre-assembled "beer tap", and that's a reasonable line length/resistance for a much wider range of beer styles. (Assuming 3/16" ID line at about 45F serving temp.)
I notice that you have 5/16 and 3/8 line listed there; the gas line size does not matter. The beer line size does, as per that Draught Quality manual and this notion of line resistance. 3/16 is a good, versatile size.
Also, make sure that the barbs are 1/16" bigger than the line ID. If they're the same size (3/16 vs. 3/16) you'll not only need clamps, but you'll need to clamp them down seriously. If the barb is 1/16" bigger, then you'll need to heat the tubing to get it on, but you probably won't need a clamp. Even for gas lines.
As for the o-ring set … I remove and clean most of my o-rings every time I keg a batch, and replace them once a year. If the keg was "reconditioned" it might have had new o-rings swapped in; they should specify. But if you're unsure, it's always nice to have a set of o-rings around in case they get funky or nicked/damaged and the keg won't hold pressure.
To sum up, this is my recommended parts list:
- [not listed] CO₂ tank
- gas QD
- gas line
- beer tap kit
- oring set
One last note, I don't know anything about John Guest fittings. I've heard about them mostly from UK homebrewers, online (I'm in the US). Everything in my keezer is standard MFL/flare fittings and/or hose-barbs.